cp's OEIS Frontend

A114147 Self-describing sequence : 1 prime between two nonprimes, then 2 primes between two nonprimes, then 4 primes, then 5, then 7, etc. The quantity of primes in each run is given by the sequence itself. (Sequence is strictly increasing and the smallest next available nonprime is used when needed).

%I A114147 #12 Jun 15 2021 11:05:12
%S A114147 1,2,4,5,7,8,11,13,17,19,20,23,29,31,37,41,42,43,47,53,59,61,67,71,72,
%T A114147 73,79,83,89,97,101,103,107,108,109,113,127,131,137,139,149,151,157,
%U A114147 163,167,168,173,179,181,191,193,197,199,211,223,227,229,233,239,240,241
%N A114147 Self-describing sequence : 1 prime between two nonprimes, then 2 primes between two nonprimes, then 4 primes, then 5, then 7, etc. The quantity of primes in each run is given by the sequence itself. (Sequence is strictly increasing and the smallest next available nonprime is used when needed).
%e A114147 Runs of primes are between brackets:
%e A114147 1,(2),4,(5,7),8,(11,13,17,19),20,(23,29,31,37,41),42,(43,47,53,59,61,67,71)
%e A114147 .^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^
%e A114147 1 prime 2 pr. 4 primes 5 primes 7 primes (etc.) = the sequence itself
%o A114147 (PARI) {m=10;k=1;v=[k];for(j=1,m,for(count=1,v[j],k=nextprime(k+1);v=concat(v,k)); while(isprime(k),k++);v=concat(v,k));for(n=1,#v,print1(v[n],","))} \\ _Klaus Brockhaus_
%K A114147 base,easy,nonn
%O A114147 1,2
%A A114147 _Eric Angelini_ and _Alexandre Wajnberg_